Long-term mortality and incidence of cardiovascular diseases and type 2 diabetes in diabetic and non-diabetic obese patients undergoing gastric banding: a controlled study
Bariatric surgery improves quality of life in morbid obesity, prevents the development of medical complications of obesity, reduces the frequency of co-morbidities, improves cardiovascular (CV) risk profile and is cost-effective in the management of obesity. A few papers, analysed in a meta-analysis by this group, have described reduced long-term mortality after bariatric surgery in comparison with non-surgery controls. Even though worldwide trends in choice of surgical techniques are changing the above mortality studies were performed using gastric banding (LAGB), vertical banded gastroplasty, and gastric bypass (RYGB). More recent studies have substantiated this finding showing a decreased number of CV events. Studies have later shown an improved life expectancy over controls also for surgery patients suffering from CV diseases and in cohorts predominantly made of male patients.
In spite of the recommendations by the International Diabetes Federation: Bariatric surgery is an appropriate treatment for people with type 2 diabetes and severe obesity (BMI ≥ 35 kg/m2) no study compared death rates in diabetic and non-diabetic patients. A few studies also showed that bariatric surgery prevents major complications of obesity, namely diabetes mellitus and hypertension, but no study compared new incident diseases in diabetic and non-diabetic patients.
The first aim of this retrospective study was to analyse long-term mortality in diabetic and non-diabetic obese patients undergoing laparoscopic gastric banding in comparison with standard medical treatment, in a group of Institutions using the gastric band with a common protocol.
This is the longest follow-up study performed to investigate mortality in LAGB as opposed to medical treatment. The study found that after a follow-up period of up to 17 years, diabetic and non-diabetic patients undergoing LAGB died less frequently than control patients, and experienced a lower number of new diseases, in particular, CV diseases and diabetes. Death counts were similarly lower, for both diabetic and non-diabetic patients, with surgery. In addition, this is the longest follow-up study performed so far, with no patient lost to follow up; the low number of patients observed after a mean period of almost 14 years simply depends on the late beginning of treatment, surgical or medical, and a longer follow-up period will make these numbers greater. Since this is an ongoing study, a further 5 years follow-up study will answer many of the as yet unresolved questions.
Benefits of bariatric surgery are probably more than simply related to improved metabolic control; improvement of metabolic control with resolution of diabetes can last several years but diabetes can re-appear after resolution, while other effects (lipid metabolism, kidney function, systolic and diastolic blood pressure) can be maintained for longer periods, being instrumental in the better overall prognosis. A few, mostly uncontrolled, studies have shown additional effects: improved endothelial function, decrease of intima-media-thickness (IMT), reduction of insulin resistance, decrease in vascular and general inflammation, increase of HDL cholesterol, decreased sympathetic activity, decreased left ventricular hypertrophy; these effects have recently been reviewed, and might explain the effects of bariatric surgery on cardiovascular disease. The study found that a small weight loss persists years after LAGB, and might be one of the reasons for decreased mortality, together with reduced incidence of diabetes and CVD; also, the number of patients with arterial hypertension (with or without organ damage, was different at the end, and can be of clinical relevance.
Finally, we should remember that at present data about reduced long-term mortality after bariatric surgery are available only for LAGB and RYGB, while there is no information available for sleeve gastrectomy, biliopancreatic diversion, and biliointestinal bypass, three types of very effective surgery.
In conclusion, this data shows that gastric banding is associated with lower mortality up to 17 years in diabetic and non-diabetic obese patients and with fewer new cases of diabetes and of CV disease. A new examination is planned for September 2017. If the above assumptions are correct, they expect an even greater preventive effect of LAGB in diabetic and non-diabetic patients with morbid obesity. The fact that benefits were similar in diabetic and non-diabetic patients is of clinical relevance; diabetologists should inform their patients of the potential benefits of bariatric surgery, not only the possible remission of diabetes, but also the protective role against excess mortality.
The LAGB10 working group includes people from Ospedale San Paolo (Annamaria Veronelli MD, Barbara Zecchini BSc, Ahmed Zakaria PhD, Francesca Frigè BSc, Luca Rossetti MD, Alberto Benetti MD, Maurizio Cristina MD, Ermanno Mantegazza BSc, Alberto Morabito PhD, Antonio E. Pontiroli MD), from IRCCS Policlinico (Enrico Mozzi MD), Ospedale San Raffaele (Alessandro Saibene MD, Michele Paganelli MD, Paola Vedani MD), from Istituto Clinico Sant Ambrogio (Giancarlo Micheletto, MD), from Istituto Multimedica (Valerio Ceriani) and from the Health Districts (Maria Grazia Angeletti MD, Mariangela Autelitano MD, Luca Cavalieri d’Oro MD, Piergiorgio Berni MD, Antonio Giampiero Russo MD).
Reference: Cardiovascular Diabetology 2016 15:39 DOI: 10.1186/s12933-016-0347-z
Authors: Antonio E Pontiroli, Ahmed S. Zakaria, Ermanno Mantegazza, Alberto Morabito, Alessandro Saibene, Enrico Mozzi & Giancarlo Micheletto